Coupler arrangement for isolation arrangement for system under test

ABSTRACT

A drive coupling arrangement for transmitting torque from a drive arrangement to a gear assembly under test has a first coupler portion attached to the gear assembly under test. The coupler has a polygonal cross-sectional configuration and a plurality of substantially planar surfaces that extend parallel to the predetermined length of axis, in the form of an assembly nut of the gear assembly under test at a rotatory terminal thereof. A second coupler portion is coupled to the drive arrangement and has an internal cross-sectional configuration that accommodates the polygonal cross-sectional configuration of the first coupler portion. The second coupler portion has a plurality of engagement portions that communicate exclusively with a predetermined number of the substantially planar surfaces of the first coupler portion, and is axially translatable along the first coupler portion. Axial loading is absorbed by an elastomeric insert that limits the extent of the engagement between first and second coupler portions. The first and second coupler portions exert a torque against one another via the substantially planar surfaces and the engagement portions, over a predetermined range that is limited by the elastomeric insert, which additionally absorbs axial loading. A resilient biasing element urges the second coupler portion axially upward toward the first coupler portion. An isolation support supports the energy transfer system so as to be translatable in at least one plane of freedom.

RELATIONSHIP TO OTHER APPLICATION

[0001] This application is a divisional patent application and acontinuation-in-part patent application of U.S. Ser. No. 09/107,091,filed Jun. 29, 1998.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates generally to systems for testingelectrical and mechanical energy transfer systems that exhibit vibratoryand other responses to electrical or mechanical input energy, and moreparticularly, to an arrangement that isolates a mechanical or electricalsystem under test and produces signals and data corresponding to aplurality of operating characteristics of the system under test inresponse to the input energy.

[0004] Description of the Related Art

[0005] Noise testing of gears to date has been attempted by methods thatrigidly mount the gear or axle assemblies in one or more planes. Someother previous attempts chose to have one of the rigidly mounted planesresonate at a frequency sympathetic to gear noise. None of thesemethods, or any other rigidly mounted test system has been successful.This is due to the lack of repeatability of the previous systems,largely as a result of interacting resonances, and external backgroundnoise that is transferred through the rigid mounting system. This isespecially true in a production test environment.

[0006] These deficiencies in the prior art are most evident in the axleindustry. At this time, the only widely accepted way of measuring gearnoise is to acquire an assembled axle and install it in a test car. Aspecially trained individual then drives the car over its typicaloperating range while carefully listening for axle gear noise. Theindividual rates the quality of axle gear noise on a scale that istypically 0 to 10. Ten is usually a perfect axle, i.e. one that has nogear noise. This method is made difficult by:

[0007] 1 The lack of available trained noise rating individuals

[0008] 2 The cost of test cars.

[0009] 3 The lack of quality roads or test tracks on which to perform arepeatable and accurate test.

[0010] 4 The time required for each test.

[0011] 5 The subjectivity that humans bring into the rating system

[0012] Typically less than a dozen axles can be tested by a majormanufacturer in one shift due to all of the above complications. Thislow number is not statistically valid when it is considered that mostmanufacturers make thousands of axles each day. Even with all of theabove problems, human testers in cars are the only widely acceptedmethod of axle testing in the industry due to the lack of a better morereliable testing method. This lack of a scientific basis for ratingaxles and gear systems is made worse when the reader considers thatmodem cars are extremely quiet, and are evolving to become more quite.This market direction increases the pressure on axle and other gearmanufacturers to make their products quieter. There is a need for asystem that offers gear and axle manufacturers a repeatable, reliable,accurate and practical way of measuring gear noise in production orlaboratory environments.

[0013] It is, therefore, an object of this invention to provide a systemfor testing an energy transfer system, such as a vehicle axle, quicklyand inexpensively, and achieving repeatable results.

SUMMARY OF THE INVENTION

[0014] The foregoing and other objects are achieved by this inventionwhich provides, in a first apparatus aspect thereof, a drive couplingarrangement for transmitting substantially exclusively torque from adrive arrangement to a gear assembly under test. In accordance with theinvention, the drive coupling arrangement is provided with a firstcoupler portion attached to the gear assembly under test. The couplerhas a polygonal cross-sectional configuration that extends continuouslyover a predetermined length of axis. The polygonal cross-sectionalconfiguration has a plurality of substantially planar surfaces thatextend parallel to the predetermined length of axis. In addition, thereis provided a second coupler portion with an internal cross-sectionalconfiguration that accommodates the polygonal cross-sectionalconfiguration of the first coupler portion. The second coupler portionhas a plurality of engagement portions that communicate exclusively witha predetermined number of the substantially planar surfaces of the firstcoupler portion. The second coupler is axially translatable along thefirst coupler portion for a portion of its predetermined length of axis.In this manner, the first and second coupler portions exert a torqueagainst one another via the substantially planar surfaces of the firstcoupler portion and the engagement portions of the second couplerportion, over a predetermined range of the portion of the predeterminedlength of axis. In addition, a resilient insert is installed within thesecond coupler portion for limiting the extent of axial translationbetween the plurality of engagement portions of said second couplerportion along said first coupler portion.

[0015] In one embodiment of the invention, the first coupler portion isin the form of an assembly nut of the gear assembly under test at arotatory terminal thereof. The polygonal cross-sectional configurationcorresponds to a hexagon and has six substantially planar surfaces. Thesecond coupler portion has three engagement portions that engage threerespective substantially planar surfaces of the first coupler portion.The second coupler portion is coupled to the drive arrangement.

[0016] A resilient biasing element urges the second coupler portionaxially toward the first coupler portion. The predetermined length ofaxis is substantially vertically arranged, the first coupler portionbeing disposed axially superior to the second coupler portion. Theresilient biasing element urges the second coupler portion axiallyupward toward the first coupler portion, whereby the first couplerportion communicates axially with the resilient insert. In a specificillustrative embodiment of the invention, the resilient insert is formedof ultra-high molecular weight polyethylene and absorbs axial loadingbetween the first and second coupler portions.

[0017] In accordance with a further apparatus aspect of the invention,there is provided an arrangement for isolating an energy transfer systemwhile it is subjected to a test process for noise, the energy transfersystem being of the type having an energy input and at least one energyoutput. In accordance with the invention, the arrangement is providedwith a base for supporting the arrangement and the energy transfersystem. An isolation support supports the energy transfer system wherebythe energy transfer system is translatable in at least one plane offreedom with respect to the base. Additionally, an engagementarrangement is provided for securing the energy transfer system to theisolation support, the engagement arrangement having a first positionwith respect to the base wherein the energy transfer system isinstallable on, and removable from, the isolation support, and a secondposition wherein the energy transfer system is secured to the isolationsupport. A first coupler portion is attached to the gear system, thecoupler portion having a polygonal cross-sectional configuration thatextends continuously over a predetermined length of axis. The polygonalcross-sectional configuration has a plurality of substantially planarsurfaces that extend parallel to the predetermined length of axis. Thereis additionally provided a second coupler portion having an internalcross-sectional configuration that accommodates the polygonalcross-sectional configuration of the first coupler portion. The secondcoupler portion has a plurality of engagement portions that communicateexclusively with a predetermined number of the substantially planarsurfaces of the first coupler portion, and are axially translatablealong the first coupler portion for a portion of the predeterminedlength of axis. Thus, the first and second coupler portions exert atorque against one another via the substantially planar surfaces of thefirst coupler portion and the engagement portions of the second couplerportion.

[0018] In one embodiment, there is further provided an energy supplycoupled to the energy transfer system for supplying energy thereto whenthe engagement arrangement is in the second position. The energytransfer system is, in one embodiment of the arrangement of the presentinvention, a mechanical energy transfer system, and in such anembodiment, the energy supply, which is a part of the arrangement of theinvention, is in the form of a source of rotatory mechanical energy. Arotatory coupler couples the source of rotatory mechanical energy to theenergy transfer system. The first coupler portion, in this embodiment ofthe invention, is an hexagonal assembly nut. The second coupler portionis resiliently urged toward the first coupler portion by operation of aresilient spring.

[0019] In a highly advantageous embodiment of the invention, themechanical energy transfer system test has forward and reversedirections of operation, and drive and coast modes of operation for eachof the forward and reverse directions of operation. The mechanicalenergy transfer system contains at least a pair of meshed elements, atleast one of the pair of meshed elements being a gear having a pluralityof gear teeth thereon, the gear teeth each having first and second geartooth surfaces for communicating with the other element of the pair ofmeshed elements. A mechanical energy transfer communication between thepair of meshed elements is effected primarily via the respective firstgear tooth surfaces during forward-drive and reverse-coast modes ofoperation, and primarily via the respective second gear tooth surfacesduring forward-coast and reverse-drive modes of operation. With such asystem under test, the arrangement of the present invention is providedwith a first acoustic sensor arranged at a first location in thevicinity of the mechanical energy transfer system for producing a firstsignal that is responsive substantially to a qualitative condition ofthe first gear tooth surfaces. A second acoustic sensor is arranged at asecond location in the vicinity of the mechanical energy transfersystem, and produces a second signal that is responsive substantially toa qualitative condition of the second gear tooth surfaces. The first andsecond locations are distal from each other on opposite sides of thepair of meshed elements.

[0020] In a further embodiment of the invention, the rotatory coupler isprovided with a resilient coupler arrangement that transmits rotatorymotion thereacross over a predetermined range of rotatory motiontransmission angles. The resilient coupler arrangement is provided withfirst and second coupler portions, the first and second coupler portionsbeing rigidly coupled rotationally to each other. Additionally, they areaxially resiliently coupled to each other, whereby the first and secondcoupler portions are synchronously rotatable over the predeterminedrange of rotatory motion transmission angles.

[0021] In yet a further embodiment of the invention, the resilientcoupler arrangement is provided with first and second coupler portions,the first and second coupler portions being rigidly coupled rotationallyto each other, and radially resiliently coupled to each other. Thus, thefirst and second coupler portions are synchronously rotatable over apredetermined range of axial displacement.

[0022] A torque sensor advantageously is interposed, in a highlyadvantageous embodiment, between the source of rotatory mechanicalenergy and the energy transfer system. The torque sensor produces asignal that is responsive to a torque applied by the source of rotatorymechanical energy to the energy transfer system. The torque sensor isprovided with a torque-transmitting element that has a predetermineddeformation characteristic. Thus, the torque-transmitting elementbecomes deformed in response to the torque that is applied by the sourceof rotatory mechanical energy to the energy transfer system. In thisembodiment of the invention, the torque sensor further is provided witha strain sensor that is coupled to the torque-transmitting element forproducing a strain signal responsive to the predetermined deformationcharacteristic of the torque-transmitting element. The strain signal,therefore, is proportional to the torque.

[0023] It is very advantageous to determine the residual torque requiredto initiate motion of the system under test. The torque sensor istherefore arranged to produce a static torque signal that is responsiveto the magnitude of the torque required to initiate rotatory motion inthe mechanical energy transfer system. In addition, it is advantageousthat the torque sensor be arranged to produce a dynamic torque signalthat is responsive to the magnitude of torque required to maintainrotatory motion in the mechanical energy transfer system.

[0024] In accordance with a further apparatus aspect of the invention.there is provided an arrangement for isolating a mechanical drive systemfor a vehicle while it is subjected to a testing process, the drivesystem being of the type having a rotatory input and at least onerotatory output. In accordance with the invention, the arrangement isprovided with a base for supporting the arrangement and the mechanicaldrive system. An isolation support supports the mechanical drive systemwhereby the mechanical drive system is translatable in at least oneplane of freedom with respect to the base. An engagement arrangementsecures the mechanical drive system to the isolation support, theengagement arrangement having a first position with respect to the basewherein the mechanical drive system is installable on, and removablefrom, the isolation support, and a second position wherein themechanical drive system is secured to the isolation support. Anengagement driver is coupled to the base and to the engagementarrangement for urging the engagement arrangement between the first andsecond positions. The engagement arrangement is coupled to theengagement driver when the engagement arrangement is in the firstposition, and isolated from the engagement driver when the engagementarrangement is in the second position. In addition, a rotatory driveapplies a rotatory drive force to the mechanical drive system, and adrive coupler transmits a torque from the rotatory drive to the rotatoryinput of the mechanical drive system. The drive coupler is itselfprovided with a first coupler portion attached to the mechanical drivesystem, the coupler having a polygonal cross-sectional configurationthat extends continuously over a predetermined length of axis. Thepolygonal cross-sectional configuration has a plurality of substantiallyplanar surfaces that extend parallel to the predetermined length ofaxis. Additionally, the drive coupler is provided with a second couplerportion having an internal cross-sectional configuration thataccommodates the polygonal cross-sectional configuration of said firstcoupler portion. The second coupler portion has a plurality ofengagement portions that communicate exclusively with a predeterminednumber of the substantially planar surfaces of said first couplerportion, and are axially translatable along the first coupler portionfor a portion of the predetermined length of axis. Thus, the first andsecond coupler portions exert a torque against one another via thesubstantially planar surfaces of said first coupler portion and theengagement portions of the second coupler portion, over a predeterminedrange of the portion of the predetermined length of axis.

[0025] In a mechanical embodiment of the invention. there areadditionally provided a rotatory load for applying a rotatory load tothe mechanical drive system, and a load coupler for coupling therotatory load to the rotatory input of the mechanical drive system. Themechanical drive system is in the form of a drive-transmitting componentfor a motor vehicle. In such an embodiment, the rotatory load applies acontrollable rotatory load thereto to simulate a plurality of vehicleoperating conditions. These include, for example, gear drive and coastconditions, as well as a gear float condition.

[0026] In accordance with a method aspect of the invention, there isprovided a method of testing a gear assembly of the type having an inputand an output. The method includes the steps of:

[0027] installing the gear assembly on a mounting arrangement thatresiliently permits motion of

[0028] installing the gear assembly on a mounting arrangement thatresiliently permits motion of the gear assembly in all directions, thegear assembly having an hexagonal assembly nut installed at a rotatoryinput thereof;

[0029] urging a coupler having three engagement surfaces resiliently andcontinuously toward the hexagonal nut, whereby the three engagementsurfaces communicate with three corresponding surfaces of the hexagonalassembly nut;

[0030] applying a torque at the coupler, whereby the gear assembly isrotatably operated;

[0031] applying a load at the output of the gear assembly; and

[0032] sensing a predetermined operating characteristic of the gearassembly.

[0033] In one embodiment of this method aspect of the invention, thestep of sensing is provided with the step of detecting acoustic energyissued by the gear assembly. Also, the step of detecting acoustic energyissued by the gear assembly is provided with the step of placing amicrophone n the vicinity of the gear assembly.

[0034] In accordance with a further embodiment of this method aspect ofthe invention, the drive and coast modes of operation are cyclical overa period that is shorter than a cycle period of the input of the gearassembly. Conversely, the period can be longer than a cycle period ofthe input of the gear assembly. This will depend, to an extent, upon theoperating ratios within the system under test. In situations where thesystem under test is an electrical system, harmonics and signaldistortions may affect the apparent cycle period in relation to thecycle period of the input energy.

[0035] In an advantageous embodiment, the first and second sensors aredisposed at respective locations that are distal from each other, withthe gear assembly interposed therebetween. This enables distinguishingbetween operating modalities of the system under test, as well asfacilitating analysis of operating characteristics of the system undertest that have directional components.

BRIEF DESCRIPTION OF THE DRAWING

[0036] Comprehension of the invention is facilitated by reading thefollowing detailed description, in conjunction with the annexed drawing,in which:

[0037]FIG. 1 is a front plan representation of an arrangement forisolating a system under test, constructed in accordance with theprinciples of the invention;

[0038]FIG. 2 is a side plan view of the embodiment of FIG. 1;

[0039]FIG. 3 is an exploded plan representation of the embodiment ofFIG. 1 showing certain drive components;

[0040]FIG. 4 is a top plan view of the embodiment of FIG. 1;

[0041]FIG. 5 is a partially phantom front plan view of a drivearrangement that supplies rotatory mechanical energy to an isolatemechanical energy transfer system under test;

[0042]FIG. 6 is side plan view of the drive system of FIG. 5;

[0043]FIG. 7 is a side plan representation of the drive system as shownin FIG. 6, enlarged to show greater detail;

[0044]FIG. 8 is a side plan view of a coupler that couples the drivesystem to the mechanical system under test;

[0045]FIG. 9 is a top plan view of the coupler of FIG. 8 showing thereinthree engagement surfaces for coupling with the flanks of an hexagonalnut (not shown in this figure) at the rotatory input of the mechanicalsystem under test;

[0046]FIG. 10 is a plan representation of a clamping arrangementconstructed in accordance with the principles of the invention, theclamping arrangement being shown in two positions;

[0047]FIG. 11 is a compact drive arrangement constructed in accordancewith the invention for coupling the rotatory output of a mechanicalenergy transfer system under test to a rotatory load;

[0048]FIG. 12 is a partially cross-sectional side plan view of thecompact drive arrangement of FIG. 11 further showing a resilientcoupling element;

[0049]FIG. 13 is a partially phantom enlarged representation of theresilient coupling element shown in FIG. 12;

[0050]FIG. 14 is an isometric representation of an arrangement forisolating a system under test, constructed in accordance with theprinciples of the invention, the system under test being an electricalenergy transfer device;

[0051]FIG. 15 is a process diagram of a typical process for conductingan energy analysis;

[0052]FIG. 16 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention;

[0053]FIG. 17 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention fordetermining bumps and nicks in a mechanical energy transfer system;

[0054]FIG. 18 is a partially cross-sectional side plan view of a compactdrive arrangement further showing a resilient engagement limitingelement that precludes engagement beyond a predetermined extent betweenthe coupler that couples the drive system and the mechanical systemunder test; and

[0055]FIG. 19 is a top end view of the arrangement of FIG. 18.

DETAILED DESCRIPTION

[0056]FIG. 1 is a front plan representation of an arrangement forisolating a system under test, constructed in accordance with theprinciples of the invention. As shown in this figure, an isolatingarrangement 10 is arranged to support in relative isolation a mechanicaldrive system in the form of a differential 11. Differential 11 is of thetype that is conventionally employed in a motor vehicle (not shown) andis intended to be tested for a variety of operating conditions, usingisolating arrangement 10. The differential is of the type having arotatory input 13 that receives rotatory mechanical energy from a drivearrangement (not shown in this figure) that will be described below. Inaddition, differential 11 has rotatory outputs 14 and 15, respectively,that produce rotatory mechanical energy in response to the rotatoryinput energy received at rotatory input 13. When employed in a motorvehicle (not shown), differential 11 is coupled to the drive shaft (notshown) of the vehicle at rotatory input 13, and rotatory outputs 14 and15 are coupled to the vehicle's drive wheels (not shown).

[0057] Differential 11 is shown to be supported on a pair of supports 18and 19 that are installed on a base 20. Each of supports 18 and 19 hasinstalled thereon a respectively associated one of resilient isolatingelements 22 and 23. A respective one of engagement arrangements 24 and25 are installed on resilient isolating elements 22 and 23. Theengagement arrangements will be described in detail hereinbelow andserve to couple differential 11 at its rotatory outputs 14 and 15whereby it is secured with respect to base 20, yet limited motion ofdifferential 11 is permitted relative to base 20.

[0058]FIG. 1 further shows a pair of load arrangements 28 and 29 thatapply a controllable load to respectively associated ones of rotatoryoutputs 14 and 15. The rotatory outputs are coupled mechanically(coupling not shown in this figure) to load arrangements 28 and 29 in amanner that facilitates limited motion of the rotatory outputs withrespect to base 20. The permissible displacement of differential 11 inaccordance with the present invention is along multiple planes offreedom, and, as will be described hereinbelow, the couplingarrangements (not shown in this figure, between rotatory outputs 14 and15 and their respective associated load arrangements 28 and 29 permitaxial and rotative degrees of freedom of motion. Such couplings will bedescribed with respect to FIGS. 9-12.

[0059]FIG. 2 is a side plan view of the embodiment of FIG. 1. Thisfigure is taken along line 2-2 of FIG. 1. In addition to some of thestructure shown in FIG. 1, FIG. 2 shows a safety cover 30 that protectsthe user (not shown) of the isolating arrangement in accordance withestablished safety standards. Elements of structure that correspond tothose discussed hereinabove with respect to FIG. 1 are similarlydesignated.

[0060]FIG. 2 shows engagement arrangement 24 having engagement arms 32and 33 that are shown in an engaged position around rotatory output 14.As will be described hereinbelow, engagement arms 32 and 33 have engagedand disengaged (not shown) positions in response to actuation of anengagement driver which is shown in this figure in the form of a linearactuator 35,

[0061] A safety cover 30 is shown to be coupled to a cover hinge 31,whereby the safety cover is rotatable thereabout in response toactuation of a cover actuator 34. In operation, the safety cover isarranged in the position shown in the figure during performance of thetesting procedure, and it is raised to a position that is not shown inorder to facilitate installation and removal of the system under test,i.e., differential 11.

[0062]FIG. 2 additionally shows a drive motor 40, which in thisembodiment, is coupled to a belt pulley 42, shown in FIG. 1.

[0063]FIG. 3 is an exploded plan representation of the embodiment ofFIG. 1 showing certain drive components. Elements of structure that havepreviously been discussed are similarly designated. The drivearrangement, and the manner by which it is coupled to differential 11,will be discussed in detail hereinbelow with respect to FIGS. 5-8.

[0064]FIG. 4 is a top plan view of the embodiment of FIG. 1. Elements ofstructure that have previously been discussed are similarly designated.Moreover, differential 11 has been removed, and therefore, is notvisible in this figure.

[0065] In FIG. 4, each of load arrangements 28 and 29 has associatedtherewith a respective one of load coupler arrangements 44 and 45, eachof which is coupled by a respective load belt 46 and 47 to a respectiveone of load units 48 and 49. Load arrangement 28 will be described indetail hereinbelow with respect to FIG. 11, and the load couplerarrangements, 44 and 45, will be described in detail with respect toFIG. 12. Referring to FIG. 4, rotatory outputs 14 and 15 (not shown inthis figure) are coupled (coupling not shown in this figure) torespectively associated ones of load coupler arrangements 44 and 45which, as previously noted, provide multiple degrees of freedom ofmovement. Load units 48 and 49, in this specific illustrative embodimentof the invention, are in the form of electric brakes or electric motors.Of course, other forms of loads can be employed in the practice of theinvention. In embodiments of the invention where the load units are inthe form of electric motors, such motors can provide simulated brakingand driving operations. Thus, in the present embodiment where theisolating arrangement is directed to the testing of a drive componentfor a vehicle, such as a differential, the load units can be operated ina drag, or generator mode, wherein the differential would be operated ina simulated drive mode. That is, the load is driven by the differential.Alternatively, the load units can be operated in a motor drive mode,wherein the differential is itself driven by the load, i.e., operated ina simulated coast mode. In a highly advantageous embodiment of theinvention, the differential can be operated and thereby tested in driveand coast modes of operation in forward and reverse directions. It is tobe remembered that during drive and coast modes of operation differentgear tooth surfaces (not shown) within the differential are caused tocommunicate with one another, thereby affording enhanced testingcapability.

[0066]FIG. 5 is a partially phantom front plan view of a drivearrangement that supplies rotatory mechanical energy to an isolatedmechanical energy transfer system under test. Elements of structure thathave previously been discussed are similarly designated. As shown inthis figure, output shafts 52 and 53 are shown protruding from thefragmented representation of rotatory outputs 14 and 15, respectively.The output shafts rotate in response to the application of a rotatorydrive at rotatory input 13.

[0067]FIG. 6 is side plan view of the drive system of FIG. 5. Theoperation of the drive arrangement that will supply a rotatory drive torotatory input 13 of differential 11 is described herein with referenceto FIGS. 5-9. As stated, drive motor 40 is coupled via a drive belt 41to belt pulley 42 which is installed on a drive shaft 55 that is shownin the figures to extend axially vertically. Belt pulley 42 contains atorque sensing arrangement (not shown) that provides an electricalsignal responsive to torque differential between the belt pulley anddrive shaft 55. The electrical signal responsive to torque (not shown)is available at signal output connector 56.

[0068] In this specific illustrative embodiment of the invention, thetorque sensing arrangement contained within belt pulley 42 and itsassociated signal output connector 56 is in the form of a strain gauge(not shown) installed to respond to the displacement of a web (notshown). That is, in the practice of this aspect of the invention, torqueis transmitted across a web whereby, for example the torque is appliedacross the periphery of the web, and an output shaft is coupled nearerto the center of the web. Of course, these may be reversed. As torque isapplied, the web is correspondingly deformed, and a strain gaugeinstalled on the web measures the deformity in the web in response tothe applied torque. Over a predetermined range of torque, thedeformation of the web, as determined by the strain gauge, can becorrelated to the magnitude of the applied torque. Signal outputconnector 56, in this specific illustrative embodiment of the invention,additionally contains circuitry (not shown) that is AC coupled to thetorque sensing arrangement, and that modulates and demodulates theresulting torque signal.

[0069] Shaft 55 is shown in FIG. 6 to be supported against axiallytransverse motion by a pair of journal bearings 58. Drive shaft 55,therefore, rotates about its axis in response to a rotatory drive energysupplied by drive motor 40 and delivered thereto by drive belt 41.

[0070] A coupling arrangement 60 that is fixed axially onto drive shaft55 permits resilient axial displacement of a coupling shaft 62 withrespect to the axis of drive shaft 55. Coupling arrangement 60 is formedof a flanged member 61 that is coupled to rotate with drive shaft 55. Afurther flanged member 63 is shown to be engaged with coupling shaft 62.Flanged members 61 and 63 are each provided with respective resilientelements 65 that facilitate the permissible axial displacement ofcoupling shaft 62 with respect to the central axis defined by driveshaft 55. The rotatory energy is transmitted across intermediate element67, with which resilient elements 65 communicate.

[0071]FIG. 7 is a side plan representation of the drive system as shownin FIG. 6, enlarged to show greater detail. As shown in FIGS. 6 and 7,the uppermost end of coupling shaft 62 is arranged to be connected torotatory input 13 of differential 11 (shown in fragmented form in thesefigures). Differential 11 is of the conventional type having anhexagonal nut 69 (FIG. 7) installed at rotatory input 13. Rotatory input13 is formed as a pinion shaft, and hexagonal nut 13 is threadedlyengaged therewith. The application of a high tightening torque tohexagonal nut 13 during assembly of the differential prevents same fromloosening during application of the rotatory energy via coupling shaft62.

[0072]FIG. 7 shows differential 11 in the process of being installedonto coupling shaft 62, and therefore hexagonal nut 69 is shown in twopositions, where it is designated 69 and 69′, respectively. Uponcompletion of the installation of differential 11, hexagonal nut 69becomes engaged with a nut driver 70. Nut driver 70 is axiallytranslatable, and therefore is shown in two positions, where it isdesignated 70 and 70′.

[0073]FIG. 8 is a side plan view of nut driver 70 that couples the drivesystem to the mechanical system under test. FIG. 9 is a top plan view ofnut driver 70 of FIG. 8 showing therein three engagement surfaces forcoupling with the flanks of an hexagonal nut (not shown in this figure)at the rotatory input of the mechanical system under test. As shown inFIG. 8 and FIG. 9, nut driver 70 has a tapered outward appearance whenviewed from the side (FIG. 8). Internally, nut driver 70 is providedwith three engagement surfaces 71. The engagement surfaces engage withthe flank surfaces of the nut (not shown) at rotatory input 13 ofdifferential 11. The nut driver is, as previously noted, axiallydisplaceable along the axis of coupling shaft 62, and is urged upwardtoward the nut at the rotatory input of the differential by operation ofa resilient spring member 72 (FIG. 6). Thus, the nut driver is urgedinto communication with the nut by operation of the light resilient biassupplied by spring 72, thereby ensuring engagement between nut driver 70and the hexagonal nut (not shown in FIGS. 8 and 9) at the rotatory inputof differential 11. It is to be noted that the light axial bias appliedby the engagement spring is negligible and affords the differential adegree of freedom of movement in the axial direction.

[0074] Referring once again to FIG. 7, sensors 73-76 are shown formonitoring various aspects of the operation of the differential inresponse to the application of the rotatory input. For example, in oneembodiment of the invention, the various sensors are configured tomonitor angular position of the rotatory input, transaxial displacementof the drive shaft, transaxial displacement of the differential inresponse to the application of the rotatory input energy, temperature inthe region of the input bearing (not shown) of the differential,acoustic noise, etc.

[0075]FIG. 10 is a plan representation of a clamping arrangementconstructed in accordance with the principles of the invention, theclamping arrangement being shown in two positions. Elements of structurethat correspond to those previously described are similarly designated.As shown, support 18 is coupled to base 20, illustratively via one ormore fasteners 140. In this embodiment, a pair of resilient supportelements 141 are disposed on support element 18 and there is supportedthereon an isolation support 142. The isolation support has a centralV-shaped region 144 in the vicinity of which are installed supportbearings 146 and 147. Rotatory output 14 of differential 11 (not shownin this figure) rests on the support bearings.

[0076] Engagement arms 32 and 33, as previously noted, have first andsecond positions corresponding to open and closed conditions. Engagementarms 32 and 33 are shown in the closed condition, wherein rotatoryoutput 14 is clamped to support bearings 146 and 147. When the supportarms are in the open position, identified as 32′ and 33′ (shown inphantom), the differential can be removed or installed onto isolationsupport 142. Actuation of the engagement arms between the open andclosed conditions is effected by operation of linear actuator 35 whichis coupled to the engagement arms by respectively associated ones ofengagement coupler links 148 and 149. Engagement coupler links 148 and149 are each coupled at a respective first ends thereof to arespectively associated one of engagement arms 32 and 33, and they eachare coupled to one another at a central pivot coupling 150. An armature151 of linear actuator 35 travels vertically to effect clamping andrelease of rotatory output 14.

[0077] When armature 151 is extended upward, engagement arms 32 and 33are urged toward rotatory output 14, whereby spring-loaded contacts 152and 153 communicate with rotatory output 14. In this embodiment, thespring-loaded contacts exert a resilient biased force against rotatoryoutput 14 facilitating the latching of the engagement arms by operationof armature 151. As shown, when the armature is extended fully upward,engagement coupler links 148 and 149 are urged beyond the point wheretheir respective axes are parallel, and therefore, the engagementcoupler links are biased against the underside of isolation support 142.It should be noted that the pivot pin (not specifically shown) coupledto armature 151 at pivot coupling 150 has a smaller diameter than theapertures in the engagement coupler links. Thus, during testing of thevibration and noise of the differential, armature 151 of linear actuator35 is essentially decoupled from engagement coupler links 148 and 149and isolation support 142.

[0078] When it is desired to remove differential 11 from isolatingarrangement 10, armature 151 is withdrawn, whereupon pivot coupling 150is translated to the location identified as 150′. In this position, theengagement arms are translated to the location shown in phantom as 32′and 33′.

[0079] In a further embodiment of the invention, one or both ofspring-loaded contacts 152 and 153 is provided with a displacementssensor 154 that produces an electrical signal, or other indication,responsive to the extent of inward translation of the spring-loadedcontact. Such an indication would be responsive to the outside dimensionof the rotatory output of differential 11, thereby providing a means fordetermining dimensional variations of the differential housing (notspecifically identified in this figure) during a production run.

[0080]FIG. 11 is a compact drive arrangement constructed in accordancewith the invention for coupling the rotatory output of a mechanicalenergy transfer system under test (not shown in this figure) to arotatory load, which will be described hereinbelow in the form of anelectric rotatory device that is operable in drive and generator modes.As shown in this figure, a load arrangement 80 is provided with a loadmotor 81 having a belt pulley 82 arranged to rotate with a load motorshaft 83.

[0081] In this specific embodiment, pulley 82 is coupled to a furtherbelt pulley 85 via a load belt 86. Pulley 85 is coupled to a tubularshaft 89 having a flanged portion 90 that is arranged in axialcommunication with tubular shaft 89. In a manner similar to that ofpulley 46 in FIG. 6, belt pulley 82 in FIG. 11 contains a torque sensingarrangement 87 that provides an electrical signal (not shown) responsiveto a torque differential between the belt pulley and load motor shaft83. The electrical signal responsive to torque is available at signaloutput connector 84, as described below.

[0082] In this specific illustrative embodiment of the invention, torquesensing arrangement 87 contained within belt pulley 82 and itsassociated signal output connector 84 include a strain gauge 88installed to respond to the displacement of a web 92. That is, in thepractice of this aspect of the invention, torque is transmitted acrossweb 92 wherein, for example, the torque is applied across the peripheryof the web, and an output shaft 98 is coupled nearer to the center ofthe web. Of course, the application of the torque may be rotationallyreversed. As the torque is applied, web 92 is correspondingly deformed,and strain gauge 88 installed on the web measures the deformity in theweb in response to the applied torque. Over a predetermined range oftorque, the deformation of web 92, as determined by measurement of theelectrical response of strain gauge 88 at signal output connector 84,can be correlated to the magnitude of the applied torque.

[0083] As described hereinabove with respect to signal output connector56 in FIG. 6, in this specific illustrative embodiment of the invention,signal output connector 84 in FIG. 11 additionally contains circuitry(not shown) that is AC coupled to the torque sensing arrangement, andthat modulates and demodulates the resulting torque signal. The torquesignal will be to a significant extent responsive to the load or drivecharacteristic of load motor 81, which is controllable by theapplication of appropriate electrical signals (not shown) or connectionof electrical loads (not shown) at electrical terminals 99 thereof.

[0084] Tubular shaft 89 is supported rotatably by ball bearings 91. Onthe other side of pulley 85 is arranged a resilient element 93 that issecured to remain in communication with pulley 85 by operation of an endcap 94. End cap 94 has internally affixed thereto a load shaft 95 thatis arranged to extend along the interior length of tubular shaft 89.Thus, notwithstanding that tubular shaft 89 is axially fixed in asupport 96, load shaft 95 will rotate with the tubular shaft but canexperience displacement transverse to axis of rotation 98. Thus, anyrotatory element (not shown in this figure) that would be coupled toload shaft 95 at its associated coupler 97 would be provided withfreedom of motion in any direction transverse to the axis of rotation ofthe load shaft, and therefore would not be constrained in the axiallytransverse direction.

[0085]FIG. 12 is a partially cross-sectional side plan view of a compactdrive arrangement similar in some respects to that of FIG. 11. Thisfigure shows a shaft support system 100 that provides the degree offreedom of motion discussed hereinabove with respect to the embodimentof FIG. 11, and additionally provides axial thrust support. Shaftsupport system 100 is provided with a pulley 101 that can be coupled toanother rotatory element (not shown) via a belt 102. The pulley is fixedto a tubular shaft 104 that is axially fixed in a support 105 by ballbearings 106. At the other end of tubular shaft 104, the tubular shaftis expanded radially to form a shaft portion 108 having a large diameterthan the central portion of the tubular shaft. A resilient couplingarrangement that is generally designated as 110 is resiliently coupledto shaft portion 108. Resilient coupling arrangement 110 is providedwith an intermediate plate 111 and an end plate 112 that are resilientlycoupled to one another whereby they rotate with tubular shaft 104. Acentral shaft 114 is coupled at its right-most end to end plate 112 soas to be rotatable therewith. The central shaft, however, experiencesfreedom of movement in all directions transverse to its axis ofrotation. Any travel of central shaft 114 toward the right hand side islimited by an end stop 115, which is arranged, in this embodiment, toprovide a measure of axial adjustment. The other end of central shaft114 is coupled to a resilient coupling arrangement which is generallydesignated as 117.

[0086]FIG. 13 is a partially phantom enlarged representation of theresilient coupling element shown in FIG. 12. Resilient coupling element117 is shown in this figure in an expanded form to facilitate thisdetailed description. Central shaft 114 (FIG. 12) has a reduced diameterend portion 120 on which is installed a flanged washer 121 having areduced diameter portion 122 and a flange 123 formed therearound. Afurther flanged element 125 is installed on reduced diameter end portion120 of central shaft 114, a shear pin 127 being disposed between flangedwasher 121 and further flanged element 125. In addition, an annularportion 128 is arranged to surround the flanged washer and the furtherflanged element, and to overlie circumferentially the axial region whereresilient element 127 is disposed. All of these elements are secured toreduced diameter end portion 120 of central shaft 114 by a fastener 129and a washer 130. As shown, fastener 129 is threadedly engaged axiallyonto the end of central shaft 114.

[0087] A support portion 132 is fixed onto further flanged element 125by fasteners 133. Support portion 132 is resiliently coupled to aflanged shaft 135 by means of studs 136. Thus, even though central shaft114 enjoys freedom of movement transverse to its axis of rotation,resilient coupling arrangement 117 provides yet further freedom ofmovement in all directions transverse to the axis of rotation forflanged shaft 135. Flanged shaft 135, in one embodiment of theinvention, is ultimately coupled to a rotatory output, such as rotatoryoutput 15 of FIG. 1. Alternatively, shaft support system 100 can be usedin the drive arrangement of FIG. 6 to provide significant degree ofmotion lateral to the axis of rotation to the drive shaft.

[0088]FIG. 14 is an isometric representation of an arrangement forisolating a system under test, the isolation system being constructed inaccordance with the principles of the invention. In this embodiment, thesystem under test is an electrical energy transfer device. As shown inthis figure, an isolation support 160 isolates an electrical energytransfer device, illustratively in the form of an electrical transformer162. The electrical transformer is secured to an isolation base 164 byoperation of a toggle locking device 165. Isolation base 164 ismechanically isolated from a ground surface 166 by a plurality ofresilient isolation elements 170. That is, the isolation base ispermitted freedom of movement in at least one plane of motion, andpreferably a plurality of planes of motion, by operation of theresilient isolation elements.

[0089] In the practice of this specific illustrative embodiment of theinvention, the resilient isolation elements have a resiliencecharacteristic that, as previously noted in regard of other embodimentsof the invention, exclude a natural frequency of isolation support 160and transformer 162. The motion of the transformer and the isolationsupport is therefore responsive substantially entirely to the electricalenergy that is transferred to or from transformer 162 via its electricalterminals 172.

[0090]FIG. 15 is a process diagram of a typical process for conductingan energy analysis of a gear system. In this known system, gears undertest 180 are driven by a drive 181, the speed of which is controlled bya speed control 183. Information relating to the drive speed isconducted to a digital data storage system 185.

[0091] Analog sensors 187 obtain analog data from gears under test 180,the analog signals from the sensors being conducted to an A/D converter188. The A/ID converter performs the conversion of the analog signals inresponse to a clock 190, and the resulting digital data is conducted todigital data storage system 185. Thus, digital data storage system 185contains the digitized analog signals obtained from sensors 187, whichdata is correlated to the speed at which gears under test 180 aredriven.

[0092] The digital data of digital data storage system 185 is convertedto the frequency domain by subjecting same to a fast Fourier transformat step 193. The resulting frequency components are then ordered at step194 and analyzed manually at step 195. At this step, the collected data,in the frequency domain, is analyzed in the context of predeterminedtest criteria. The pass/fail decision is then made at step 197, and ifthe predetermined criteria is not met, a “fail” indication is producedat step 198. Otherwise, a “pass” indication is issued at step 199.

[0093]FIG. 16 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention. Asshow in this figure, gears under test 201 are driven into rotation by adrive system 202, which also drives an encoder 204. Encoder 204 deliverssignals responsive to the rotation of gears under test 201 to an A/Dconverter 206. In this embodiment, the signal from encoder 204 serves asa pacing clock for the A/D converter. Information relating to noise anddisplacement issued by the gears under test is collected by analogsensors 207. The resulting analog signals are conducted to A/D converter206 where they are converted to digital signals correlated to therotation of drive system 202.

[0094] The digital signals from A/D converter 206 are conducted to adigital data store 210 where they are maintained in correlation to thedrive information obtained from encoder 204. In this specificillustrative embodiment of the invention, the digital data is storedtwo-dimensionally, wherein sensor signal amplitude is identified withthe y-axis, and rotational position is identified with the x-axis. Thecorrelated digital data is subjected to a fast Fourier transform at step212 wherein the data is converted into its frequency components.

[0095] Data in the frequency domain is subjected to processing at step214, where a power spectrum density is created using a data window. Thepower spectrum density data is then analyzed harmonically at step 215 todetermine its relationship with predetermined test criteria. Thedecision whether the power spectrum density data passes or fails withrespect to predetermined test criteria is made at step 216, and thepredetermined criteria is not met, a “fail” indication is produced atstep 217. Otherwise, a “pass” indication is issued at step 218.

[0096]FIG. 17 is a diagram of a process for conducting an analysis 230in accordance with the principles of the present invention fordetermining bumps and nicks in a mechanical energy transfer system. Asshow in this figure, gears under test 231 are driven into rotation by adrive system 232, via a torque sensor 234. Torque sensor 234 deliverssignals responsive to the rotatory force supplied to gears under test231 to an A/D converter 236. Information relating to noise anddisplacement issued by the gears under test is collected by noisesensors 237, which may include velocity sensors (not shown in thisfigure), accelerometers (not shown in this figure), microphones (notshown in this figure), etc. The resulting noise signals are conducted toA/D converter 236 where they are converted to digital signals correlatedto the torque applied by drive system 232 to gears under test 231.

[0097] The digital signals from A/D converter 236 are conducted to adigital data store 240 where they are maintained in correlation to thedrive information obtained from torque sensor 234. In this specificillustrative embodiment of the invention, the digital data is stored astwo two-dimensional data sets, wherein noise sensor signal amplitude isidentified with a first y-axis, and time is identified with the x-axis.The amplitude of the torque signal is identified with a second y-axis,and time is again identified with the x-axis.

[0098] Correlated data from digital data store 240 is subjected toanalysis at step 242, wherein peaks that occur simultaneously in thetorque and noise signal waveforms are identified. These peaks are thenmeasured at step 244 to determine whether they exceed predeterminedthresholds. Those peaks that exceed the predetermined thresholds arethen tested at step 245 against the harmonics of each gear toothfrequency, to determine whether the peaks correspond to anomalousconditions.

[0099] The decision whether the gears under test pass or fail withrespect to predetermined test criteria is made at step 246, and if thepredetermined criteria is not met, a “fail” indication is produced atstep 247. Otherwise, a “pass” indication is issued at step 248. In someembodiments of the invention, a calculation of the severity of the bumpsor nicks that caused the anomalous conditions is calculated at step 249.

[0100] In one embodiment of the process of FIG. 17, analysis isperformed using only the torque data derived from torque sensor 234,without correlation to the noise data obtained from noise sensor 237. Inthis embodiment, therefore, noise sensor 237 need not be provided, asthe noise signal therefrom is not used. Thus, torque sensor 234 deliverssignals responsive to the rotatory force supplied to gears under test231 to A/D converter 236, and the digital data is stored as a singletwo-dimensional data set, wherein the amplitude of the torque signal isidentified with the y-axis, and time is identified with the x-axis.

[0101] Peaks in the torque signal are then measured at step 244 todetermine whether they exceed a predetermined threshold. Those peaksthat exceed the predetermined thresholds are then tested at step 245against the harmonics of each gear tooth frequency, to determine whetherthe peaks correspond to anomalous conditions.

[0102] The decision whether the gears under test pass or fail withrespect to predetermined test criteria is made at step 246, and if thepredetermined criteria is not met, a “fail” indication is produced atstep 247. Otherwise, a “pass” indication is issued at step 248. Aspreviously noted, a calculation of the severity of the bumps or nicksthat caused the anomalous condition is calculated at step 249.

[0103]FIG. 18 is a partially cross-sectional side plan view of a compactdrive arrangement 260 constructed in accordance with the invention,further showing a resilient engagement limiting element 262 that notonly precludes engagement of a nut driver 265 with an hexagonal nut 269beyond a predetermined extent, but also absorbs axial loading that wouldresult in a noise component. In a highly advantageous specificillustrative embodiment of the invention, resilient engagement limitingelement 262 is formed ultrahigh molecular weight polyethylene (UHMW-PE)and is dimensioned to preclude communication between nut driver 265 anda flange structure 270 that is, in this embodiment, arranged to surroundhexagonal nut 269. In the arrangement illustrated in this figure, ashaft 274, on which hexagonal nut 269 is installed, is in axialcommunication with resilient engagement limiting element 262. Anycommunication between resilient engagement limiting element 262 and anyportion of the driven mechanical system under test other than thepredetermined flats of hexagonal nut 269, such as flange structure 270,will result in the generation of a noise that may reduce the quality ofthe test.

[0104]FIG. 19 is a partially cross-sectional top end view of compactdrive arrangement 260 of FIG. 18. As shown, nut driver 265 is configuredinternally to communicate with only three flats, such as flat 272 ofhexagonal nut 269, which is installed on a shaft 271. Communication withthe remaining three flats is avoided by formation of a space 274 betweennut driver 265 and hexagonal nut 269.

[0105] Although the invention has been described in terms of specificembodiments and applications, persons skilled in the art can, in lightof this teaching, generate additional embodiments without exceeding thescope or departing from the spirit of the claimed invention.Accordingly, it is to be understood that the drawing and description inthis disclosure are proffered to facilitate comprehension of theinvention, and should not be construed to limit the scope thereof.

What is claimed is:
 1. A drive coupling arrangement for transmittingsubstantially exclusively torque from a drive arrangement to a gearassembly under test, the drive coupling arrangement comprising: a firstcoupler portion attached to the gear assembly under test, said couplerhaving a polygonal cross-sectional configuration that extendscontinuously over a predetermined length of axis, the polygonalcross-sectional configuration having a plurality of substantially planarsurfaces that extend parallel to the predetermined length of axis; asecond coupler portion having an internal cross-sectional configurationthat accommodates the polygonal cross-sectional configuration of saidfirst coupler portion, said second coupler portion having a plurality ofengagement portions, each of which communicating exclusively withrespectively associated ones of a predetermined number of thesubstantially planar surfaces of said first coupler portion, and beingaxially translatable along said first coupler portion for a portion ofthe predetermined length of axis, wherein said first and second couplerportions exert a non-slip torque against one another via thesubstantially planar surfaces of said first coupler portion and theengagement portions of said second coupler portion, over a predeterminedrange of the portion of the predetermined length of axis; and aresilient insert installed within the second coupler portion forlimiting the extent of axial translation between the plurality ofengagement portions of said second coupler portion along said firstcoupler portion.
 2. The drive coupling arrangement of claim 1, whereinsaid first coupler portion comprises an assembly nut of the gearassembly under test at a rotatory terminal thereof.
 3. The drivecoupling arrangement of claim 1, wherein the polygonal cross-sectionalconfiguration corresponds to a hexagon having six substantially planarsurfaces.
 4. The drive coupling arrangement of claim 3, wherein saidsecond coupler portion has three engagement portions that engage threerespective substantially planar surfaces of said first coupler portion.5. The coupling arrangement of claim 1, wherein said second couplerportion is coupled to the drive arrangement.
 6. The coupling arrangementof claim 1, wherein there is further provided a resilient biasingelement for urging said second coupler portion axially toward said firstcoupler portion, whereby said first coupler portion communicates axiallywith said resilient insert.
 7. The coupling arrangement of claim 6,wherein the predetermined length of axis is substantially verticallyarranged, said first coupler portion being disposed axially superior tosaid second coupler portion, said resilient biasing element urging saidsecond coupler portion axially upward toward said first coupler portion,and said resilient insert is formed of ultra-high molecular weightpolyethylene and absorbs axial loading between said first and secondcoupler portions.
 8. An arrangement for isolating a gear system while itis subjected to a test process for noise, the gear system being of thetype having an energy input and at least one energy output, thearrangement comprising: a base for supporting the arrangement and thegear system; isolation support means for supporting the gear systemwhereby the gear system is translatable in at least one plane of freedomwith respect to said base; engagement means for securing the gear systemto said isolation support means, a first coupler portion attached to thegear system, said coupler having a polygonal cross-sectionalconfiguration that extends continuously over a predetermined length ofaxis, the polygonal cross-sectional configuration having a plurality ofsubstantially planar surfaces that extend parallel to the predeterminedlength of axis; and a second coupler portion having an internalcross-sectional configuration that accommodates the polygonalcross-sectional configuration of said first coupler portion, said secondcoupler portion having a plurality of engagement portions thatcommunicate exclusively with a predetermined number of the substantiallyplanar surfaces of said first coupler portion, and being axiallytranslatable along said first coupler portion for a portion of thepredetermined length of axis, wherein said first and second couplerportions exert a torque against one another via the substantially planarsurfaces of said first coupler portion and the engagement portions ofsaid second coupler portion, over a predetermined range of the portionof the predetermined length of axis.
 9. The arrangement of claim 8,wherein the gear system is a mechanical energy transfer system, and saidenergy supply means comprises a source of rotatory mechanical energy.10. The arrangement of claim 9, wherein there is further providedrotatory coupling means for coupling said source of rotatory mechanicalenergy to the mechanical energy transfer system.
 11. The arrangement ofclaim 9, wherein said first coupler portion comprises an assembly nut ofthe gear system at a rotatory terminal thereof.
 12. The arrangement ofclaim 11, wherein said mechanical energy transfer system has forward andreverse directions of operation, and drive and coast modes of operationfor each of the forward and reverse directions of operation.
 13. Thearrangement of claim 12, wherein there the mechanical energy transfersystem contains at least a pair of meshed gears, at least one of saidpair of meshed gears having a plurality of gear teeth thereon, said gearteeth each having first and second gear tooth surfaces for communicatingwith the other gear of said pair of meshed gears, a mechanical energytransfer communication between the pair of meshed gears being effectedprimarily via the respective first gear tooth surfaces duringforward-drive and reverse-coast modes of operation, and primarily viathe respective second gear tooth surfaces during forward-coast andreverse-drive modes of operation.
 14. The arrangement of claim 13,wherein there is further provided a first acoustic sensor arranged at afirst location in the vicinity of the mechanical energy transfer systemfor producing a first signal responsive substantially to a qualitativecondition of said first gear tooth surfaces.
 15. The arrangement ofclaim 14, wherein there is further provided a second acoustic sensorarranged at a second location in the vicinity of the mechanical energytransfer system for producing a second signal responsive substantiallyto a qualitative condition of said second gear tooth surfaces.
 16. Thearrangement of claim 15, wherein the first and second locations aredistal from each other on opposite sides of said pair of meshedelements.
 17. The arrangement of claim 16, wherein there is furtherprovided torque sensor means interposed between said source of rotatorymechanical energy and said second coupler portion for producing a signalresponsive to a torque applied by said source of rotatory mechanicalenergy to the energy transfer system.
 18. The arrangement of claim 17,wherein said torque sensor means comprises: a torque-transmittingelement having a predetermined deformation characteristic, saidtorque-transmitting element being deformed in response to the torqueapplied by said source of rotatory mechanical energy to the energytransfer system; and a strain sensor coupled to said torque-transmittingelement for producing a strain signal responsive to the predetermineddeformation characteristic of said torque-transmitting element.
 19. Thearrangement of claim 17, wherein said torque sensor means is arranged toproduce a static torque signal responsive to the magnitude of torquerequired to initiate rotatory motion in said mechanical energy transfersystem.
 20. The arrangement of claim 17, wherein said torque sensormeans is arranged to produce a dynamic torque signal responsive to themagnitude of torque required to maintain rotatory motion in saidmechanical energy transfer system.
 21. An arrangement for isolating amechanical drive system for a vehicle while it is subjected to a testingprocess, the drive system being of the type having a rotatory input andat least one rotatory output, the arrangement comprising: a base forsupporting the arrangement and the mechanical drive system; isolationsupport means for supporting the mechanical drive system whereby themechanical drive system is translatable in at least one plane of freedomwith respect to said base; engagement means for securing the mechanicaldrive system to said isolation support means, said engagement meanshaving a first position with respect to said base wherein the mechanicaldrive system is installable on, and removable from, said isolationsupport means, and a second position wherein the mechanical drive systemis secured to said isolation support means; engagement driver meanscoupled to said base and to said engagement means for urging saidengagement means between said first and second positions, saidengagement means being coupled to said engagement driver means when saidengagement means is in said first position, and isolated from saidengagement driver means when said engagement means is in said secondposition; rotatory drive means for applying a rotatory drive force tothe mechanical drive system; and drive coupling means for transmitting atorque from said rotatory drive means to the rotatory input of themechanical drive system, said drive coupling means being provided with;a first coupler portion attached to the mechanical drive system, saidcoupler having a polygonal cross-sectional configuration that extendscontinuously over a predetermined length of axis, the polygonalcross-sectional configuration having a plurality of substantially planarsurfaces that extend parallel to the predetermined length of axis; and asecond coupler portion having an internal cross-sectional configurationthat accommodates the polygonal cross-sectional configuration of saidfirst coupler portion, said second coupler portion having a plurality ofengagement portions that communicate exclusively with a predeterminednumber of the substantially planar surfaces of said first couplerportion, and being axially translatable along said first coupler portionfor a portion of the predetermined length of axis, wherein said firstand second coupler portions exert a torque against one another via thesubstantially planar surfaces of said first coupler portion and theengagement portions of said second coupler portion, over a predeterminedrange of the portion of the predetermined length of axis.
 22. Thearrangement of claim 21, wherein there are further provided: rotatoryload means for applying a rotatory load to the mechanical drive system;and load coupling means for coupling said rotatory load means to arotatory output of the mechanical drive system.
 23. A method of testinga gear assembly of the type having an input and an output, the methodcomprising the steps of: installing the gear assembly on a mountingarrangement that resiliently permits motion of the gear assembly in alldirections, the gear assembly having an hexagonal assembly nut installedat a rotatory input thereof; urging a coupler having three engagementsurfaces resiliently and continuously toward the hexagonal nut, wherebythe three engagement surfaces communicate with three correspondingsurfaces of the hexagonal assembly nut; applying a torque at thecoupler, whereby the gear assembly is rotatably operated; applying aload at the output of the gear assembly; and sensing a predeterminedoperating characteristic of the gear assembly.
 24. The method of claim23, wherein said step of applying a torque is performed in a selectableone of drive and coast modes of operation of the gear